public static Rule Parse(string input, int index)
{
int id = int.Parse(input.Substring(0, index));
input = input.Substring(index + 1).Trim();
Rule rule = null;
if (input.StartsWith('\"'))
{
rule = new BaseRule(id, input);
}
else
{
index = input.IndexOf('|');
if (index >= 0)
{
rule = new MultiRule(id, input);
}
else
{
rule = new StandardRule(id, input, -1);
}
}
return(rule);
}
protected override bool match2(Dictionary <int, Rule> rules, string message, ref int index)
{
//To match this rule in Part2, each looping rule is matched as many times as possible before returning
if (ID == 0)
{
//Assume rule 0 only has 2 rules
MultiRule rule1 = (MultiRule)rules[requiredRules[0]];
MultiRule rule2 = (MultiRule)rules[requiredRules[1]];
for (int firstRuleMatches = 0; ; firstRuleMatches++)
{
index = 0;
if (!rule1.matchLooping(rules, message, ref index, firstRuleMatches))
{
if (index >= message.Length)
{
return(false);
}
else
{
continue; //Try more!!!
}
}
int baseIndex = index;
for (int secondRuleMatches = 0; ; secondRuleMatches++)
{
index = baseIndex; //Reset the index to the end of rule1 matches
if (rule2.matchLooping(rules, message, ref index, secondRuleMatches))
{
if (index == message.Length)
{
return(true);
}
}
else
{
if (index >= message.Length)
{
break;
}
else
{
continue;
}
}
}
}
}
else
{
bool result = true;
foreach (int ruleId in requiredRules)
{
if (!rules[ruleId].match2(rules, message, ref index))
{
result = false;
}
}
return(result);
}
}
public Tuple <Dictionary <int, Rule>, string[]> ParseInput()
{
var lines = Input.Split("\n", StringSplitOptions.TrimEntries);
var i = 0;
var rules = new Dictionary <int, Rule>();
while (!string.IsNullOrEmpty(lines[i]))
{
var a = lines[i].Split(':', StringSplitOptions.TrimEntries);
int r = int.Parse(a[0]);
if (a[1].Contains('\"'))
{
rules[r] = BasicRule.Parse(a[1]);
}
else if (a[1].Contains('|'))
{
rules[r] = OrRule.Parse(a[1]);
}
else
{
rules[r] = MultiRule.Parse(a[1]);
}
i++;
}
return(Tuple.Create(rules, lines.Skip(i + 1).ToArray()));
}
static Rule[] ParseRules(IEnumerable <string> ruleText)
{
int maxRule = ruleText.Max(line => int.Parse(line.Substring(0, line.IndexOf(':'))));
Rule[] rules = new Rule[maxRule + 1];
var defRegex = new Regex(@"^([0-9]+): (.*)$");
var charRegex = new Regex(@"""(\w)""");
var followingRegex = new Regex(@"( [0-9]+)+");
foreach (string line in ruleText)
{
var outline = defRegex.Match(line);
int index = int.Parse(outline.Groups[1].Value);
string body = outline.Groups[2].Value;
var charMatch = charRegex.Match(body);
if (charMatch.Success)
{
rules[index] = new LetterRule {
Letter = charMatch.Groups[1].Value[0]
};
continue;
}
var followMatch = followingRegex.Matches(line);
if (!followMatch.Any())
{
throw new Exception();
}
var ruleIndices = followMatch
.Select(match => match.Value.Split(" ", StringSplitOptions.RemoveEmptyEntries)
.Select(int.Parse).ToArray());
var followRules = ruleIndices
.Select <int[], Rule>(indices => new FollowingRules {
RuleIndices = indices, Rules = rules
}).ToArray();
if (followRules.Length == 1)
{
rules[index] = followRules[0];
}
else
{
rules[index] = new MultiRule {
Rules = followRules
}
};
}
return(rules);
}
public OrRule(MultiRule a, MultiRule b)
{
this.a = a;
this.b = b;
}